Total body weight is usually employed to calculate the amount of l-T(4) to be administered in patients with thyroid diseases. The aim of this study was to evaluate the effect of body composition on l-T(4) requirements. Body composition was assessed by dual energy x-ray absorptiometry in 75 patients on TSH-suppressive l-T(4) therapy after conventional thyroid ablation for differentiated cancer. The mean daily dose of l-T(4) was lower in normal-weight (127.5 +/- 21.3 mug/d) vs. overweight (139.4 +/- 24.5) and obese (151.3 +/- 29.1) subjects. There was a much stronger association between the l-T(4) dosage and lean body mass (P < 0.001, r = 0.667) compared with fat mass (P = 0.023, r = 0.26). Measurement of regional tissue composition showed peripheral lean mass as the best correlate with the dose of l-T(4) (r = 0.679, P < 0.001) whereas no correlation was observed with peripheral fat mass. In conclusion, individual l-T(4) requirements are dependent on lean body mass. Age- and gender-related differences in l-T(4) needs reflect different proportions of lean mass over the total body weight. An estimate of lean mass may be helpful to shorten the time required to attain a stable dose of l-T(4), particularly in subjects with high body mass index values that may be due either to increased muscular mass or to obesity.
Background: Previous studies have demonstrated a high prevalence of thyroperoxidase antibodies (TPOAb) and autoimmune hypothyroidism in breast cancer (BC). These studies have been performed in BC patients generally 20-30 days after mastectomy. It is known that stress may have an influence on the immune system and a relation between stressful events and the onset or worsening of autoimmune thyroid disorders has been reported by several authors. The aim of the study was to evaluate the prevalence of autoimmune thyroid disease in patients with nodular breast disease selected for surgery before any treatment. Our hypothesis was that the high prevalence of thyroid autoimmune disorders in BC is independent of stressful events represented by surgery and/or anaesthetic procedures. Methods: Our series included 61 consecutive women aged 52.8G10.2 yrs (mean ageGS.D.) with nodular breast disease selected for breast surgery: 36 out of 61 of them (59%) had BC and 25 out of 61 had benign breast disease (BBD). Controls included 100 healthy age-matched women. All patients and control subjects were submitted to clinical, ultrasound thyroid evaluation and serum-free thyroxine (FT4), serum-free tri-iodothyronine (FT3), TSH, TPOAb and thyroglobulin antibodies (TgAb) determination. Results: Mean FT3, FT4 and TSH concentration showed no differences between BC patients, BBD patients and controls. The prevalence of TPOAb in BC patients (12/36: 33.33%) was significantly higher than in BBD patients (5/25: 20%) (P!0.01) and in controls (8/100: 8%) (P!0.01). Similarly, the prevalence of TgAb in BC patients was 12 out of 36 (33.33%) significantly higher than that detected in BBD patients (4/25: 16%) (P!0.01) and in controls (12/100: 12%) (P!0.01). Of the 36 BC patients, 20 showed a diffuse hypoechogenicity of the thyroid gland to ultrasound evaluation, significantly higher than in BBD (7/25: 28%) (PZ0.03). Of the 20 BC patients who showed a hypoechogenic pattern of thyroid gland, 10 (50%) were associated with antithyroid antibodies positivity (TAb). This finding was present in two of seven BBD (28.57%) (P!0.0001). Only two controls showed focal hypoechogenicity of the thyroid gland. Generally, 24 out of 36 (66.7%) of BC and 9 out of 25 (36%) of BBD (PZ0.02) had signs of thyroid autoimmunity consistent with the hypoechogenic pattern of thyroid gland associated or not with TAb; 2 out of 36 (5.55%) of BC and 1 out of 25 (4%) of BBD patients had autoimmune hypothyroidism and no hypothyroidism was found in controls. Conclusions: The results of this study confirm the strong relation between thyroid autoimmunity and BC. This finding is independent of stressful events represented by surgery or anaesthetic procedures. The present data call attention to the usefulness of screening for autoimmune thyroid disorders in patients with nodular breast disease selected for surgery.
A high prevalence of autoimmune thyroid disease (AITD) has been described in Turner's syndrome (TS) but the extent of this association is controversial for the prevalence of thyroid autoantibody and the clinical impact of thyroid dysfunction. In this study we searched for thyroid disease and thyroid autoantibodies in patients with TS. Seventy-five unselected TS patients (age range 3-30 years) were studied. Sera were tested for thyroid hormones, thyrotropin (TSH), thyroglobulin (TG-ab) and thyroperoxidase (TPO-ab) antibodies. The TSH-receptor antibodies with thyroid-stimulating (TS-ab) or TSH-blocking activity (TSHB-ab) were measured in the IgG fraction using a bioassay. Ten out of 75 (13.3%) TS patients had AITD: eight had autoimmune thyroiditis (AT) (six with subclinical and two with overt hypothyroidism and one with euthyroidism) and one had Graves' disease. The prevalence of AITD increased significantly (p < 0.05) from the first (15%) to the third (30%) decade of life. The prevalence of TPO-ab and/or TG-ab (20%) was higher (p < 0.05) in TS than in age-matched female controls and increased from the first (15%) to the third (30%) decade of life. Clinical AITD was diagnosed in 46% of TS patients with TPO-ab and/or TG-ab. Thyroid-stimulating antibody was detected in the hyperthyroid patient, and TSHB-ab was found in one of eight patients with hypothyroid AT. It was concluded that: TS patients are at higher than average risk of developing AITD not only in adolescence and adult age but also in childhood; hypothyroidism, mainly subclinical, is the most frequent thyroid dysfunction; elevated TPO-ab and/or TG-ab alone do not imply thyroid dysfunction; TS-ab or TSHB-ab are always associated with thyroid dysfunction although most cases of autoimmune hypothyroidism are not due to the latter antibody.
Thyroid dysfunction is associated with metabolic changes that affect mass and adipocyte function, as well as lipid and carbohydrate metabolism. Adipose tissue performs complex metabolic and endocrine functions. Leptin and adiponectin are two of the most important adipocytokines, both involved in the regulation of intermediate metabolism. The aim of this study was to evaluate the relationships between thyroid status and circulating levels of the two adipose tissue hormones. We studied 15 patients with hyperthyroidism, 15 patients with hypothyroidism and 15 euthyroid subjects, all matched by sex, age and body mass index (BMI). Serum concentrations of free thyroxine, free tri-iodothyronine, thyrotropin, leptin and adiponectin and anthropometric parameters (weight, height, BMI) were assessed. No significant difference was found among the 3 groups, as assessed by Student's t-test, both for adiponectin and leptin. We conclude that metabolic changes associated with thyroid dysfunction are not related to variations in serum levels of adiponectin or leptin.
A high incidence of anti-thyroid antibodies (TAb) has been found in patients with breast cancer (BC). The aim of this study was to evaluate the prognostic value of TAb in a group of 47 women submitted to mastectomy for high malignancy degree BC. All patients were evaluated for thyroid disorders after breast surgery and before any anti-tumoral adjuvant therapy. Five yr after BC diagnosis 31/47 (65.9%) patients were alive (survivors group: SG) and 16/47 (34.1%) were dead (deaths group: DG). The overall prevalence of TAb was 15/47 (31.9%): 14/31 (45.1%) in SG and 1/16 (6.2%) in DG (p=0.008). Five-yr mortality was 15/32 (46.9%) in TAb- and 1/15 (6.7%) in TAb+ patients (p=0.01). Eight out of 47 (17.0%) patients had Hashimoto's thyroiditis and 7 of them (87.5%) were in SG. Estrogen receptor (ER) was measured in 43/47 (91.5%) BC specimens. ER was detected in 19/30 (63.0%) patients in SG and 3/13 (23.1%) in DG (p=0.01). Five-yr mortality was 10/21 (47.6%) in ER- and 3/22 (13.6%) in ER+ patients (p=0.008). Absence of ER expression [odds ratio (OR) 6.54; p=0.006] and absence of TAb (OR 9.37; p=0.03) were related to a higher mortality rate. TAb were detected in 8/21 (38.1%) ER- and in 7/22 (31.8%) ER+ patients; no relation was found between ER expression and TAb positivity (p=ns). Patients with ER+ and TAb+ have a better prognosis and the absence of a significant relationship between these two parameters suggests an independent prognostic role in high malignancy degree BC women.
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